The Photochemical Raction of 2-Alkoxy-1,4-naphthoquinones with Olefins. II. The Formation of Tetrahydropyran-ring Compounds

The photochemical reaction of 2-alkoxy-1,4-naphthoquinones with numerous types of olefins was investigated. The reaction was found to proceed smoothly in possible combinations of quinones and olefins to give photo-addition compounds in good yields. The structure of the addition compounds was determined to be 10 by their elemental analyses, mass, IR, PMR, and chemical reactions. The photo-addition reaction is characterized by the formation of a tetrahydropyran ring. This type of photo-addition reaction has not been previously known. The scope and limitations of the new photochemical reaction were described.